Spring for folding eyeglasses.



PATENTED 0.0T. 27,1903- F. BIRKENSTEIN. SPRING FOR FOLDING EYEGLASSES.

APPLICATION FILED OCT. 7, 1902.

NO MODEL.

UNITED STATES Patented October 2'7, 1963".

PATENT FFICE.

FERDINAND BIRKENSTEIN, OF FRANKFORT-ON-THE-MAIN, GERMANY,

ASSIGNOR TO THE FIRM OF F. BIRKENSTEIN 85 00., OF FRANKFORT-ON-THE-MAIN, GERMANY.

SPRING FOR F-OLDING EYEGLASSES.

SPECIFICATION forming part of Letters Patent No. 742,384, dated October27, 1903.

Application filed October '7, 1902. Serial No- 126,297. (No model.)

To aZZ whom it may concern:

Be it known that I, FERDINAND BIRKEN- STEIN, manufacturer, residing atWolfsgangstrasse N0. 80, Frankfort-on-the-Main, Germany,have inventednew and useful Improvements in Folding Eyeglasses, of which thefollowing is a specification.

The attachment ,of the springs of folding eyeglasses to the edges of theglass frames or rims is commonly effected by means of small screws whichpass through holes provided in the spring itself. These holes causeconsiderable weakness of the spring at the point of its attachment, justwhere it is subjected to the maximum bending stress, so that a breakageof the spring almost always takes place at that point. Hitherto it hasonly been possible to strengthen this part of the spring by increasingits width, and this could only be effected by making the entire folderstronger and heavier.

The object of the present invention is to obviate this drawback and toinsure a greater durability of the spring, particularly at its points ofattachment, while retaining the present lightness of construction of thefolder. To effect this object, the folder-spring according to thepresent invention is formed at those parts where the screw-holes areprovided with extensions in width which are bent over in trough-likeform to receive the glass frames or rims between them, so that thematerial of the frames or rims can be. firmly clamped in such a mannerby and between the bentover parts of the spring that theattachmentcurity in this case,the jaws may have mounted on them a smallplate having downwardlybent extensions in such a manner that they areheld fast by the screw, while the bentover extensions engage with therim of the glass through slots or recesses in the j aw, and thus preventall movement of the parts.

In the accompanying drawings, which illustrate the present invention,Figure 1 is a perspective view of one example of the folderspring. Fig.2 is a front view of a pair of eyeglasses having a folder-spring likethat shown in Fig. 1. of a modification of the spring. Fig. 4: is afront view of a pair of glasses having the spring shown in Fig. 3. Fig.5 is a perspective View, on an enlarged scale, showinga furthermodification of the example shown in Figs. 3 and 4; and Fig. 6 is asection on the line 6 6 of Fig. 5.

The spring a is provided at those parts Fig. 3 is a perspective viewwhere it is to be attached to the glasses with I holes I) for thereception of the screws, and at these parts the breadth of the spring isenlarged, so asto form bent-over flaps c, which embrace the rims orframes of the glasses. The small guide-hooks (Z for the clamping jawsare made in one piece with the spring;

but they may be affixed separately thereto. In the form of constructionshown in Figs. 3 and t the bent-over flaps c are prolonged downward insuch a manner as to form clamping-jaws for attaching the spring to therims or frames of the glasses. In these figures, I) also indicates theholes through which the screws pass, and cl the small guide-hooks forthe clamping-jaws.

As shown in'Figs. 5 and 6, a small plate (2 is provided, which serves toprevent the movement of the parts and the shearing of the screws in theholes I). This smallplate is placed on one side of the clamping-jaws c,and it is provided with downwardly-bent pins or lugs f, which engagewith the rim h of the glasses through slots gin the clamping-jaws 0.

Now what I claim, and desire to secure by Letters Patent, is thefollowing:

1. In folding eyeglasses, the combination with the glass-frames, of afolder-spring having extensions in width which are turned over intrough-like form to receive between them and clamp the parts of theframes to which the spring is attached.

2. In folding eyeglasses, the combination with the glass rims orframes,of afolder-sprin g having lateral flaps which receive between Intestimony whereof I have signed my them the parts of the rims 0r framesto which name to this specification in the presence of 10 the springsare attached, plates placed over two subscribing Witnesses.

said lateral flaps and havin spikes passin 3 1 1 5 through notchesinsaid flap? and penetrating FERDINAND bIRKENb'l into the glass rims 0rframes and means for \Vitnesses:

clamping said plates and flaps together upon JEAN GRUND,

CARL GRUND.

the rims 01' frames.

